Influence of plasma protease inhibitors and Trasylol on trypsin-induced bradykinin-release in vitro and in vivo. Protease inhibitors and trypsin-induced bradykinin release.

The release in dog plasma of bradykinin in an experimental model in vitro and in vivo secondary to the addition of increasing amounts of trypsin was studied. The release was correlated with the degree of saturation of the plasma protease inhibitors, alpha 2-macroglobulin and alpha 1-antitrypsin, without and in the presence of Trasylol. There was a good correlation between the saturation of alpha 2-macroglobulin with trypsin and the release of bradykinin. A simultaneous fall in blood pressure was seen in the in vivo experiments. alpha 1-Antitrypsin was unable to block this tryptic activity in the absence of free alpha 2-macroglobulin. In the presence of Trasylol, the saturation of alpha 2-macroglobulin was not followed by any significant kinin liberation and the blood pressure remained stable.